If you want the best air suspension - check out TotalLoadControl. Adds over 5,000 pounds of lift to level any load and dramatically improve safety and control. Yes, TLC is more expensive than "inside the coil" but its 5X the power with heavy-duty Goodyear 9" air springs (the largest used on any 1/2-ton truck) and improves almost all aspects of your truck's performance.
Please check us out on the Z vendor forum which has a lot of great Z info with pics of some trick installations (mainly of the gauge panel; TLC itself installs easily without modification) or our website.
Thanks for the shout out Brandon.